Hi Colin. Yes, the “eight different reasons” (at least) has really fueled my frustrations, if you can’t already tell from my bug-splat comments 
It seems like the 21.0 release is full of problems because the various stack traces have very few similarities. I do, however, see Ruby more often than not at the top of the stack which is disconcerting.
My main point to begin with was, the 3D Connexion drivers may indeed be causing problems, but I’d scrutinize crash logs before pointing that finger because SU 21.0 crashes if you look at it wrong